1. Field of the Invention
The present invention relates to a cooling apparatus for cooling a refrigerant, that boils when receiving heat from a heat generating element, through heat exchange between the boiling refrigerant and a cooling medium.
2. Description of the Related Art
For example, a cooling apparatus boiling and condensing refrigerant is known for cooling an inverter which conducts a large amount of electric current for operating a vehicle. This cooling apparatus contains a refrigerant container for storing therein liquid refrigerant and a heat dissipating portion for cooling the refrigerant, that boils when receiving heat generated by a heat generating element mounted on the refrigerant container, through heat exchange between the boiling refrigerant and a cooling medium (for example, cooling air or cooling water).
Heat generated from the heat generating element is transferred to the heat dissipating portion from the refrigerant container when the refrigerant boils or vaporizes and is emitted to the cooling medium as latent heat when the refrigerant is cooled to condense at the heat dissipating portion.
In many conventional cooling apparatuses, however, the heat dissipating portion contains tubes and fins and is fabricated by inserting the tubes in the refrigerant container. In this construction, the dimensional accuracy needs to be strictly controlled, for the tubes and holes in the refrigerant container into which the tubes are inserted, in order to prevent the leakage of the refrigerant, this causing a problem that the production of the components becomes difficult.
In addition, as a construction needs to be provided on the refrigerant container for controlling the insertion amount of the tubes, a volume occupied by the refrigerant container becomes large for the height of the cooling apparatus. As a result, as the volume of the heat dissipating portion becomes small, this causes a problem that the cooling capability becomes insufficient.
The invention was made in view of the above situation and an object thereof is to provide a cooling apparatus boiling and condensing refrigerant which can facilitate the production of the components involved and reduce the volume that is to be occupied by a refrigerant encapsulating portion (a refrigerant tank portion) so as to expand a heat dissipating surface area of the cooling apparatus.
According to an aspect of the invention, there is provided a cooling apparatus boiling and condensing refrigerant having a refrigerant tank portion having a heat generating element mounted on a surface thereof and adapted to store therein a refrigerant, and a heat exchanging portion for executing heat exchange between the refrigerant that boils by being heated by heat generated by the heat generating element and a cooling medium, and constructed, as a whole, by stacking a number of plate-like members, wherein first openings that form part of the refrigerant passages and second openings that form part of the cooling passages are provided in the plurality of plate-like members which are used for the heat exchanging portion, the first opening portions being adapted to establish a communication with an internal space of the refrigerant tank portion.
According to the construction, as the cooling apparatus including the refrigerant tank portion and the heat exchanging portion has a stacked construction as a whole, tubes and fins, which are used to constitute the conventional heat dissipating portion, can be eliminated. As a result, as there exists no tube needing to be assembled to be inserted into the refrigerant tank portion, no strict dimension control of component parts is required and therefore the production of component parts is facilitated. In addition, as the adoption of the stacked construction allows the component parts to be assembled from one direction, automation of the assembling process can be easily arranged.
Furthermore, as the elimination of the conventional component parts obviates the necessity of providing the construction for controlling the inserting amount of the tubes into the refrigerant tank portion on the same refrigerant tank portion, the volume of the refrigerant tank portion which occupies part of the overall volume of the cooling apparatus can be reduced. As a result, the heat dissipating surface area of the cooling apparatus can be expanded to thereby improve the heat dissipating performance thereof.
According to another aspect of the invention, there is provided a cooling apparatus boiling and condensing refrigerant having a refrigerant tank portion having a heat generating element mounted on a surface thereof and adapted to store therein a refrigerant, a refrigerant diffusing portion for diffusing the refrigerant that boils by being warmed by heat generated by the heat generating element and a heat exchanging portion provided between the refrigerant tank portion and the refrigerant diffusing portion for executing heat exchange between the boiling refrigerant and a cooling medium, and constructed, as a whole, by stacking a number of plate-like members, wherein first openings that form part of refrigerant passages and second openings that form part of cooling passages are provided in those of the plurality of plate-like members which are used for the heat exchanging portion, the first opening portions being adapted to establish communications with internal spaces of the refrigerant tank portion and the refrigerant diffusing portion.
According to the construction, as the cooling apparatus including the refrigerant tank portion, as well as the heat exchanging portion and the refrigerant diffusing portion has a stacked construction as a whole, tubes and fins, which are used to constitute the conventional heat dissipating portion, can be eliminated. As a result, as there exists no tube needing to be assembled to be inserted into the refrigerant tank portion, no strict dimensional control of component parts is required and therefore the production of component parts is facilitated. In addition, as the adoption of the stacked construction allows the component parts to be assembled from one direction, the automation of the assembling process can be easily arranged.
Furthermore, since the elimination of the conventional tubes obviates the necessity of providing the construction for controlling the inserting amount of the tubes into the refrigerant tank portion on the same refrigerant tank portion, the volume of the refrigerant tank portion which occupies part of the overall volume of the cooling apparatus can be reduced. As a result, the heat dissipating surface area of the cooling apparatus can be expanded to thereby improve the heat dissipating performance thereof.
In the cooling apparatus according to the invention, two different types of plate-like members, which are different from each other in at least the location of the second openings, are used for the heat exchanging portion, the two types of plate-like members being stacked alternately so that the second openings thereof partly communicate with each other.
According to the construction, the second openings provided in the two types of plate-like members partly communicate with each other to thereby form the cooling passages through which the cooling medium is allowed to flow.
In the cooling apparatus according to the invention, the two types of plate-like members each have pillar portions which divide the respective second openings, the locations of the pillar portions being different from each other between the two types of plate-like members.
According to the construction, as the plate-like portions have the pillar portions, the strength of the plate-like portions can be ensured. In addition, as the locations of the pillar portions are different from each other between the two types of plate-like portions, winding cooling passages, not linear cooling passages, extending around the pillar portions, can be formed.
In the cooling apparatus according to the invention, inner fins are inserted in the refrigerant passages and the cooling passages or either of them for increasing the heat conducting surface area.
According to the construction, the heat exchange between the refrigerant and the cooling medium can be promoted to thereby increase the cooling performance of the cooling apparatus.
In the cooling apparatus according to the invention, the inner fins are each formed into a configuration having an elasticity.
As this occurs, in inserting the inner fins into the refrigerant passages or the cooling passages, as the fins can be inserted while being compressed, there is no risk that the fins are hooked at intermediate positions along the length of the passages and therefore the fins can be inserted into the passages easily and securely. In addition, after having been so inserted into the passages, the inner fins can be joined to inner wall surfaces of the passages by utilizing the elasticity thereof, and therefore, joining failures of the inner fins can be advantageously reduced.
In the cooling apparatus according to the invention, the internal capacity of the refrigerant tank portion is set larger than a sum of an internal capacity formed by the first openings of the entirety of the heat exchanging portion and the internal capacity of the refrigerant diffusing portion.
According to the construction, even when the cooling apparatus is put in an inclined posture, there is no risk that part of the boiling surface dries out (dry-out), whereby a deterioration in performance when tilted can be prevented.
In the cooling apparatus according to the invention, the first openings provided in the heat exchanging portion are each constituted by a group of opening holes in which a plurality of opening holes, that are each opened in a circular or rectangular configuration, are formed in a continuous fashion.
According to the construction, the number of pillar portions formed between the opening holes can be increased and, as this can help attempt to increase the condensing surface area, the construction can contribute to the improvement in cooling performance. In addition, as the internal capacity formed by the first openings in the heat exchanging portion on the refrigerant side is reduced, the deterioration in cooling performance of the cooling apparatus, when it is used while being in a tilted posture, can advantageously be suppressed.
In the cooling apparatus according to the invention, tank portions are provided on the plate-like members used for the heat exchanging portion at ends of the second openings, and heat exchanging areas are provided on the plate-like members constituting the refrigerant tank portion and the refrigerant diffusing portion for executing heat exchange between the cooling medium that flows through the tank portions and the refrigerant.
According to the construction, as the heat exchanging areas for executing heat exchange between the refrigerant and the cooling medium are increased, an improvement in performance can be expected. Further, as heat exchanging areas are provided, the internal capacity of the refrigerant side can be increased, and when the cooling apparatus is used while being in a tilted posture, the deterioration in cooling performance thereof can be suppressed.
In the cooling apparatus according to the invention, the heat generating element is mounted at a substantially central portion of the surface of the refrigerant tank portion, and the internal capacity of a portion of the refrigerant tank portion, which belongs to an area thereof which is excluded from an area thereof where the heat generating element is mounted, is set larger than the internal capacity of a portion of the refrigerant tank portion which belongs to the area thereof where the heat generating element is mounted.
According to the construction, as the internal capacity of the portion of the refrigerant tank portion, which belongs to the area of the same tank portion which is excluded from the area thereof where the heat generating element is mounted, can be set larger even when the cooling apparatus is used while being in the tilted posture, there is no risk that the vaporizing surface dries out partially (dry-out), thereby making it possible to prevent the deterioration in cooling performance while the cooling apparatus is being tilted.
According to a further aspect of the invention, there is provided a cooling apparatus boiling and condensing refrigerant having a refrigerant tank portion having a heat generating element mounted on a surface thereof and adapted to store therein a refrigerant, and a heat exchanging portion for executing heat exchange between the refrigerant, that boils by being warmed by heat generated by the heat generating element, and a cooling medium, and constructed, as a whole, by stacking a number of plate-like members, wherein the heat exchanging portion is constructed by alternately stacking the first plate-like members having first openings, that form part of refrigerant passages to communicate with an internal space in the refrigerant tank portion, and second openings, that form part of cooling passages, and the second plate-like members having at least the first openings, the second plate-like member being set to be thinner than the first plate-like member so as to have a function as a fin.
According to the construction, as the cooling apparatus including the refrigerant tank portion and the heat exchanging portion has a stacked construction as a whole, tubes and fins, which are used to constitute the conventional heat dissipating portion, can be eliminated. As a result, as there exists no tube needing to be assembled to be inserted into the refrigerant tank portion, no strict dimensional control of component parts is required and therefore the production of component parts is facilitated. In addition, as the adoption of the stacked construction allows the component parts to be assembled from one direction, the automation of the assembling process can be easily arranged.
Furthermore, as the elimination of the conventional tubes obviates the necessity of providing the construction for controlling the inserting amount of the tubes into the refrigerant tank portion on the same refrigerant tank portion, the volume of the refrigerant tank portion which occupies part of the overall volume of the cooling apparatus can be reduced. As a result, the heat dissipating surface area of the cooling apparatus can be expanded to thereby improve the heat dissipating performance thereof.
In addition, as both upper and lower surfaces of the second opening formed in the first plate-like member are closed with the thinner second plate-like members, the second plate-like members can play the role of a fin relative to the cooling medium, whereby the heat conducting surface area on the cooling medium side can be increased to thereby improve the cooling performance.
According to another aspect of the invention, there is provided a cooling apparatus boiling and condensing refrigerant having a refrigerant tank portion having a heat generating element mounted on a surface thereof and adapted to store therein a refrigerant, a refrigerant diffusing portion for diffusing the refrigerant that boils by being warmed by heat generated by the heat generating element, and a heat exchanging portion provided between the refrigerant tank portion and the refrigerant diffusing portion for executing heat exchange between the boiling refrigerant and a cooling medium and constructed, as a whole, by stacking a number of plate-like members, wherein the heat exchanging portion is constructed by alternately stacking the first plate-like members having first openings, that form part of refrigerant passages to communicate with internal spaces in the refrigerant tank portion and the refrigerant diffusing portion, and second openings, that form part of cooling passages, and the second plate-like members having at least the first openings, the second plate-like member being set to be thinner than the first plate-like member so as to have a function as a fin.
According to the construction, as the cooling apparatus including the refrigerant tank portion and the heat exchanging portion, as well as the refrigerant diffusing portion, has a stacked construction as a whole, tubes and fins can be eliminated which are used to constitute the conventional heat dissipating portion. As a result, as there exists no tube needing to be assembled to be inserted into the refrigerant tank portion, no strict dimensional control of component parts is required and therefore the production of component parts is facilitated. In addition, as the adoption of the stacked construction allows the component parts to be assembled from one direction, the automation of the assembling process can be easily arranged.
Furthermore, as the elimination of the conventional tubes obviates the necessity of providing the construction for controlling the inserting amount of the tubes into the refrigerant tank portion on the same refrigerant tank portion, the volume of the refrigerant tank portion, which occupies part of the overall volume of the cooling apparatus, can be reduced. As a result, the heat dissipating surface area of the cooling apparatus can be expanded to thereby improve the heat dissipating performance thereof.
In the cooling apparatus according to the invention, the second plate-like member has a communication port which communicates with the second opening formed in the first plate-like member.
According to the construction, since the cooling medium is allowed not only to flow through the second opening in parallel with the first plate-like member but also to pass through the communication port formed in the second plate-like member so as to flow through the heat exchanging portion in a direction in which the plate-like members are stacked, the cooling performance can be increased.
In the cooling apparatus according to the invention, the second opening in the first plate-like member is provided in such a manner as to be divided into a second opening portion and another second opening portion with a pillar portion being left therebetween, and the communication port formed in the second plate-like member is adapted to communicate with both the second opening portion and the other second opening portion.
According to the construction, as the second opening (the second opening portion and the other second opening portion) is formed in the first plate-like member with the pillar portion being left therebetween, the strength of the first plate-like member is increased. In addition, as the communication port formed in the second plate-like member communicates with both one second opening portion and another second opening portion, cooling water is allowed to flow in a winding fashion by flowing around the pillar portions.
In the cooling apparatus according to the invention, a sacrificial material is affixed to one or both sides of at least either of the first plate-like member and the second plate-like member which are both made of a metal.
According to the construction, the affixation of the sacrificial material to the plate-like member can restrain the corrosion of the plate-like member by the cooling medium, the leakage of gas hermetically sealed therein thereby being prevented.
In addition, the sacrificial material is a metallic material having a lower corrosion resistance against the cooling medium than that of the plate-like members and, for example, in the event that the plate-like member is made of aluminum, the sacrificial member can be an aluminum material containing Zn (zinc).
In the cooling apparatus according to the invention, the second-plate like member has a plurality of cut and erected pieces which are provided in such a manner as to be cut and erected from the surface thereof, and these cut and erected pieces protrude into the second opening formed in the first plate-like member.
According to the construction, as the cut and erected pieces are provided in such a manner as to protrude into the second opening through which the cooling medium flows, vertical vortexes can be induced in the cooling medium so as to promote heat conduction (turbulent flows).
In the cooling apparatus according to the invention, the second plate-like member is provided such that the surface of the second plate-like member becomes irregular within the second opening formed in the first plate-like member.
According to the construction, as the cooling medium flows along the irregular configuration in the vicinity of the surface of the second plate-like member, vertical vortexes can be induced in the cooling medium to promote heat conduction (turbulent flows).
In the cooling apparatus according to the invention, the first openings formed in the plurality of plate-like members that are used for the heat exchanging portion are adapted to communicate with one another to form refrigerant passages that communicate with the refrigerant tank portion, and barrier wall portions are provided in the refrigerant passages for disturbing the flow of the refrigerant.
As the refrigerant tank portion and the heat exchanging portion of the cooling apparatus according to the invention are adjacent to each other in the direction in which the plate-like members are stacked, when the thermal load from the heat generating element becomes large, there may occur a case where the liquid refrigerant boils up into the heat exchanging portion which should normally be filled with vaporized refrigerant. As this occurs, and in the event that the liquid refrigerant penetrates into the heat exchanging portion, the actual condensing surface area of the heat exchanging portion is reduced, this reducing, in turn, the cooling performance of the cooling apparatus. The boiling up of liquid refrigerant can be prevented by providing barrier wall portions (for example, a labyrinth construction) within the refrigerant passages which establish a communicate between the refrigerant tank portion and the heat exchanging portion, whereby the deterioration in cooling performance can be suppressed.
In the cooling apparatus according to the invention, the cooling medium is liquid such as water.
In the case of utilizing water as the cooling medium, heat dissipating fins that are used in a cooling apparatus utilizing air as the cooling medium can be eliminated by adopting the stacked construction in which the plurality of plate-like members are stacked as a cooling apparatus.
The present invention may be more fully understood from the description of preferred embodiment of the invention, as set forth below, together with the accompanying drawings.